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Abstracts - Krycia Figueiredo Azevedo

BEHAVIORAL STATE DEPENDENCY: A GUSTATORY RECEPTOR HAS UPREGULATED EXPRESSION IN THE ANTENNAE OF HOST-SEEKING MOTIVATED FEMALE Rhodnius prolixus

Krycia Figueiredo Azevedo1*, Jose Manuel Latorre-Estivalis2, Marcelo Lorenzo1

1 IRR-FIOCRUZ, Belo Horizonte, Brazil; marcelo@minas.fiocruz.br

2 CREG-Univ. La Plata, La Plata, Argentina; josmantorres@gmail.com

* Correspondence: krycia.azevedo@minas.fiocruz.br

The publication of the genome sequence of Rhodnius prolixus, a vector of Chagas disease, has allowed the search for functional questions regarding numerous triatomine genes. After molting, triatomines present a state-dependent host search motivation. Transcriptomic studies allowed us to detect several sensory-related genes that present consistently high expression in the antennae of larval and adult bugs. Furthermore, several of those genes presented a down or up regulated expression pattern nicely correlated with the maturation of host search behavior. As we intend to uncover the molecular bases of triatomine sensory processes, our group chose several of these genes as targets for functional de-orphanization. The present study aimed at characterizing whether GR27, one of the gustatory receptors most highly expressed in bug antennae, suffers any change in expression depending on adult female post-ecdysis age, as such changes may suggest its function goes through maturation. RNA samples of antennae of adult females (20 per sample) belonging to two age points (4 replicates per point) were prepared from whole antennae based on the Trizol® method. The ages chosen (0, 20 days) belong to two distinct age conditions between which responsiveness to hosts becomes effective in female bugs. Samples were then used to compare GR27 expression levels in these two conditions by means of qPCR using α-tubulin and G6PDH as reference genes. Data showed that GR27 suffers an up-regulation through this age interval in the antennae of females. Ongoing RNAi experiments with this gene will allow us to detect an altered phenotype that may offer clues about the sensory function of GR27. More studies need to be performed to confirm if these fluctuations in transcript abundance affect sensory physiology. We suggest that GR27 may be associated with the detection of host cues and that this detection needs to undergo a maturation process before bugs become responsive to them.

Financial support: FAPEMIG, INCT-EM, CNPq, IRR-FIOCRUZ